U.S. patent number 8,681,467 [Application Number 13/326,543] was granted by the patent office on 2014-03-25 for surge protection apparatus and method using the same.
This patent grant is currently assigned to Electronics and Telecommunications Research Institute. The grantee listed for this patent is Kwang-Uk Chu, Kyung-Hoon Lee, Up Namkoong. Invention is credited to Kwang-Uk Chu, Kyung-Hoon Lee, Up Namkoong.
United States Patent |
8,681,467 |
Chu , et al. |
March 25, 2014 |
Surge protection apparatus and method using the same
Abstract
A surge protection apparatus is provided. The surge protection
apparatus includes a non-linear element unit, a signal generation
unit, and a switching element unit. The non-linear element unit
enables an electrical surge to pass therethrough by rapidly
decreasing resistance of the non-linear element unit when the
difference in voltage between two ends of the non-linear element
unit is equal to or greater than a predetermined value. The signal
generation unit generates a control signal in response to current
which passes through the non-linear element unit. The switching
element unit switches the status thereof in response to the control
signal.
Inventors: |
Chu; Kwang-Uk (Daejeon,
KR), Namkoong; Up (Buyeo-gun, KR), Lee;
Kyung-Hoon (Daejeon, KR) |
Applicant: |
Name |
City |
State |
Country |
Type |
Chu; Kwang-Uk
Namkoong; Up
Lee; Kyung-Hoon |
Daejeon
Buyeo-gun
Daejeon |
N/A
N/A
N/A |
KR
KR
KR |
|
|
Assignee: |
Electronics and Telecommunications
Research Institute (Daejeon, KR)
|
Family
ID: |
45560688 |
Appl.
No.: |
13/326,543 |
Filed: |
December 15, 2011 |
Prior Publication Data
|
|
|
|
Document
Identifier |
Publication Date |
|
US 20120268855 A1 |
Oct 25, 2012 |
|
Foreign Application Priority Data
|
|
|
|
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Apr 25, 2011 [KR] |
|
|
10-2011-0038414 |
|
Current U.S.
Class: |
361/117;
361/127 |
Current CPC
Class: |
H02H
9/041 (20130101); H02H 9/042 (20130101) |
Current International
Class: |
H02H
1/00 (20060101) |
Field of
Search: |
;361/117-120,127 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
Primary Examiner: Nguyen; Danny
Attorney, Agent or Firm: LRK Patent Law Firm
Claims
What is claimed is:
1. A surge protection apparatus comprising: a non-linear element
unit for enabling an electrical surge to pass therethrough by
rapidly decreasing resistance of the non-linear element unit when a
difference in voltage between two ends of the non-linear element
unit is equal to or greater than a predetermined value; a signal
generation unit for generating a control signal in response to
current which passes through the non-linear element unit; and a
switching element unit for changing switching status in response to
the control signal, wherein the signal generation unit comprises a
transformer; and wherein each of a zener diode and a capacitor is
parallel-connected to a secondary coil of the transformer.
2. The surge protection apparatus as set forth in claim 1, wherein
the non-linear element unit comprises at least one of a varistor, a
gas discharge tube, and a transient voltage suppression diode.
3. The surge protection apparatus as set forth in claim 1, wherein
the signal generation unit comprises a transformer and a zener
diode.
4. The surge protection apparatus as set forth in claim 1, wherein
the signal generation unit comprises one or more resistors.
5. The surge protection apparatus as set forth in claim 1, wherein
the signal generation unit comprises one or more resistors and a
zener diode.
6. The surge protection apparatus as set forth in claim 1, wherein
the switching element unit comprises at least one of a thyristor
and a relay.
7. The surge protection apparatus as set forth in claim 6, wherein
the thyristor is a Silicon Controlled Rectifier (SCR).
8. A surge protection method comprising: enabling an electrical
surge to pass through by rapidly decreasing resistance of a
non-linear element unit when a difference in voltage between two
ends of the non-linear element unit is equal to or greater than a
predetermined value; generating a control signal in response to
current, which passes through the non-linear element unit, using a
signal generation unit; and changing switching status of a
switching element unit in response to the control signal, wherein
the signal generation unit comprises a transformer; and wherein
each of a zener diode and a capacitor is parallel-connected to a
secondary coil of the transformer.
9. The surge protection method as set forth in claim 8, wherein the
generating the control signal comprises generating a control signal
wherein voltage of the generated control signal is restricted to an
allowable range of the switching element unit by using a zener
diode or a capacitor.
Description
CROSS REFERENCE TO RELATED APPLICATION
This application claims the benefit of Korean Patent Application
No. 10-2011-0038414, filed on Apr. 25, 2011, which is hereby
incorporated by reference in its entirety into this
application.
BACKGROUND OF THE INVENTION
1. Technical Field
The present invention relates generally to a surge protection
apparatus and a method using the same, and, more particularly, to a
surge protection apparatus and a method using the same, which
blocks a high power surge or a high energy surge for a long time
period.
2. Description of the Related Art
Generally, when a surge greater than rated voltage or current flows
into an electricity/electronic apparatus, the
electricity/electronic may malfunction or be damaged. Here, a surge
is a pulse created by an instant and sudden large increase in
voltage or current.
Surges are normally generated because of lighting and a sudden load
change, and are generated when a High Altitude Electro-Magnetic
Pulse (HEMP), obtained when a nuclear device is exploded at an
altitude of 30 km or higher, is coupled to a power cable or a
communication cable.
FIG. 1 illustrates the conditions of a Pulse Current Injection
(PIC) test that commercial power cables of facilities are subjected
to in conformity of MIL-STD-188-125-1 which is the military
standard of the United States of America related to HEMP
protection.
Referring to FIG. 1, a current of 10 A or less should flow through
a load resistor when a high power short pulse is applied, and
performance degradation or physical damage should not occur when
high energy intermediate pulse or long pulse is applied.
Generally, in order to block the inflow of a surge, a surge
protection apparatus is provided at the front end of a specific
circuit, and a filter is provided at the rear end of the circuit,
so that the component of a surge which is equal to or greater than
a set value is first blocked using the surge protection apparatus,
and then the unnecessary remaining component of a frequency band is
removed using the filter.
Prior art surge protection apparatuses include non-linear elements,
such as a varistor, a gas discharge tube and a transient voltage
suppression diode, in which resistance rapidly decreases when the
difference in voltage between the two ends of such a surge
protection apparatus is equal to or greater than a preset
value.
Such a surge protection apparatus may effectively block a high
power surge such as a short pulse. However, in the case of a high
energy surge persisting for a long time period, such as an
intermediate pulse or a long pulse, there are problems of
performance degradation and physical damage because a non-linear
element is overheated or electrodes are damaged.
SUMMARY OF THE INVENTION
Accordingly, the present invention has been made keeping in mind
the above problems occurring in the prior art, and an object of the
present invention is to provide a surge protection apparatus and a
method using the same, which blocks a high power surge and a high
energy surge for a long period of time.
In order to accomplish the above object, the present invention
provides a In order to accomplish the above object, the present
invention provides a surge protection apparatus, including a
non-linear element unit for enabling an electrical surge to pass
therethrough by rapidly decreasing resistance of the non-linear
element unit when a difference in voltage between two ends of the
non-linear element unit is equal to or greater than a predetermined
value; a signal generation unit for generating a control signal in
response to current which passes through the non-linear element
unit; and a switching element unit for changing switching status
thereof in response to the control signal.
The non-linear element unit may include at least one of a varistor,
a gas discharge tube, and a transient voltage suppression
diode.
The signal generation unit may include a transformer.
The signal generation unit may include a transformer and a zener
diode.
The signal generation unit may include a transformer, a zener
diode, and a capacitor.
The signal generation unit may include one or more resistors.
The signal generation unit may include one or more resistors and a
zener diode.
The switching element unit may include at least one of a thyristor
and a relay.
The thyristor is a Silicon Controlled Rectifier (SCR).
In order to accomplish the above object, the present invention
provides a surge protection method, including enabling an
electrical surge to pass through by rapidly decreasing resistance
of a non-linear element unit when a difference in voltage between
two ends of the non-linear element unit is equal to or greater than
a predetermined value; generating a control signal in response to
current, which passes through the non-linear element unit, using a
signal generation unit; and changing switching status of a
switching element unit in response to the control signal.
The generating the control signal may include generating a control
signal wherein voltage of the generated control signal is
restricted to an allowable range of the switching element unit
using a zener diode or a capacitor.
BRIEF DESCRIPTION OF THE DRAWINGS
The above and other objects, features and advantages of the present
invention will be more clearly understood from the following
detailed description taken in conjunction with the accompanying
drawings, in which:
FIG. 1 is a table illustrating the conditions of a Pulse Current
Injection (PIC) test that commercial power cables of facilities are
subjected to in conformity of MIL-STD-188-125-1 which is the
military standard of the United States of America related to HEMP
protection;
FIG. 2 is a view schematically illustrating the configuration of a
surge protection apparatus according to an embodiment of the
present invention;
FIG. 3 is a view illustrating a circuit to which the surge
protection apparatus according to the embodiment of the present
invention is applied;
FIG. 4 is a view illustrating a simulation circuit which simulates
the operation of a surge protection apparatus according to a first
embodiment of the present invention;
FIG. 5 is a view illustrating the results of a simulation performed
by the simulation circuit of FIG. 4;
FIG. 6 is a view illustrating a simulation circuit which simulates
the operation of a surge protection apparatus according to a second
embodiment of the present invention;
FIG. 7 is a view illustrating the results of a simulation performed
by the simulation circuit of FIG. 6;
FIG. 8 is a view illustrating a simulation circuit which simulates
the operation of a surge protection apparatus according to a third
embodiment of the present invention;
FIG. 9 is a view illustrating the results of a simulation performed
by the simulation circuit of FIG. 8;
FIGS. 10 and 11 are views illustrating simulation circuits which
simulate the operations of surge protection apparatuses according
to fourth and fifth embodiments of the present invention;
FIGS. 12 and 13 are views illustrating simulation circuits which
simulate the operations of surge protection apparatuses according
to sixth and seventh embodiments of the present invention; and
FIG. 14 is a flowchart illustrating a surge protection method
according to an embodiment of the present invention.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
The present invention will be described in detail with reference to
the accompanying drawings below. Here, in cases where the
description would be repetitive and detailed descriptions of
well-known functions or configurations would unnecessarily obscure
the gist of the present invention, the detailed descriptions will
be omitted. The embodiments of the present invention are provided
to complete the explanation of the present invention to those
skilled in the art. Therefore, the shapes and sizes of, components
in the drawings may be exaggerated to provide a more exact
description.
Hereinafter, a surge protection apparatus and a method using the
same according to embodiments of the present invention will be
described in detail with reference to the accompanying
drawings.
FIG. 2 is a view schematically illustrating the configuration of a
surge protection apparatus according to an embodiment of the
present invention. FIG. 3 is a view illustrating a circuit to which
the surge protection apparatus according to the embodiment of the
present invention is applied.
Referring to FIG. 2, a surge protection apparatus 100 includes a
non-linear element unit 110, a signal generation unit 120, and a
switching element unit 130.
The non-linear element unit 110 enables an electrical surge whose
voltage is higher than the predetermine voltage to pass through the
non-linear element unit 110 in such a way that resistance increases
when the difference in voltage between the two ends is equal to or
less than a predetermine value, and resistance rapidly decreases
when the difference in voltage between the two ends is equal to or
greater than the predetermine value.
The non-linear element unit 110 according to the embodiment of the
present invention includes at least one of a varistor, a gas
discharge tube, and a transient voltage suppression diode.
The signal generation unit 120 generates a control signal used to
switch the status of the switching element unit 130 in response to
a current which passes through the non-linear element unit 110.
The signal generation unit 120 according to the embodiment of the
present invention includes a transformer.
The signal generation unit 120 according to the embodiment of the
present invention includes a transformer and a zener diode.
The signal generation unit 120 according to the embodiment of the
present invention includes a transformer, a zener diode, and a
capacitor.
The signal generation unit 120 according to the embodiment of the
present invention includes one or more resistors.
The signal generation unit 120 according to the embodiment of the
present invention includes one or more resistors, and a zener
diode.
The switching element unit 130 switches the switching status
thereof in response to the control signal.
The switching element unit 130 according to the embodiment of the
present invention includes at least one of a thyristor and a
relay.
The thyristor is a Silicon Controlled Rectifier (SCR).
Referring to FIG. 3, a circuit to which the surge protection
apparatus 100 according to the embodiment of the present invention
is applied includes a surge generation source 10 for generating
pulses which satisfy the conditions of the PCI test of FIG. 1 on
the input side of the surge protection apparatus 100, includes a
filter 20 for removing unnecessary remaining components of a
frequency band on the output side of the surge protection apparatus
100, and includes a load resistor 30.
In detail, when the surge protection apparatus 100 receives a surge
which is equal to or higher than a predetermine value from the
surge generation source 10, the resistance of the non-linear
element unit 110 rapidly decreases, so that surge current flows to
the ground through the signal generation unit 120.
The signal generation unit 120 generates a control signal in
response to the surge current which flows from the non-linear
element unit 110, thereby switching the switching status of the
switching element unit 130 from off to on. Here, if the resistance
of the switched-on switching element unit 130 is noticeably less
than the resistance of the non-linear element unit 110 which was
rapidly decreased, most of the surge, which flows after the
switching element unit 130 has been switched on, flows to the
ground through the switching element unit 130.
Next, simulation circuits which simulate the operation of the surge
protection apparatus 100 and the results thereof will be described
in detail with reference to FIGS. 4 to 9.
FIG. 4 is a view illustrating a simulation circuit which simulates
the operation of a surge protection apparatus according to a first
embodiment of the present invention, and FIG. 5 is a view
illustrating the results of a simulation performed by the
simulation circuit of FIG. 4.
Referring to FIG. 4, a simulation circuit according to a first
embodiment of the present invention includes a surge generation
source 40 for generating short pulses which satisfy the conditions
of the PCI test of FIG. 1, the surge protection apparatus 100, the
filter 20 for removing high-frequency components, and the load
resistor Load_Z 30. Here, the filter 20 includes an inductor (506
uH) and a capacitor C1 (30 uF).
The surge protection apparatus 100 according to the first
embodiment of the present invention includes a non-linear element
unit 110 which has a Metal Oxide Varistor (MOV) having a clamping
voltage of 375 V, a signal generation unit 120 which has a toroidal
transformer having a primary coil wound 5 times and a secondary
coil wound 70 times, and a switching element unit 130 which has an
SCR having an on-control voltage of 2V.
Referring to FIG. 5, FIG. 5 illustrates the results of simulation
performed on current which passes through the non-linear element
unit 110 when a short pulse (rising time: 20 ns, Full Width Half
Maximum (FWHM): 550 ns, and peak current: 2.5 kA) which satisfies
the conditions of the PCI test of FIG. 1 is input to the surge
protection apparatus 100, that is, MOV let-through current 501,
simulation performed on current which passes through the switching
element unit 130, that is, SCR let-through current 502, and
simulation performed on current which passes through the load
resistor 30, that is, load resistor let-through current 503,
respectively.
In detail, when voltage which is equal to or greater than a
predetermine value (375V) is applied to two ends of the non-linear
element unit 110 because of the short pulse generated by the surge
generation source 40 and the resistance of the non-linear element
unit 110 rapidly decreases from dozens of M.OMEGA. to several
.OMEGA. or less, pulse current passes through the signal generation
unit 120, that is, the primary coil of the transformer, and then
flows to the ground. Thereafter, voltage, which is in proportion to
the ratio of the times that the primary coil of the transformer is
wound (5 times) to the times that the secondary coil is wound (70
times), is induced to the secondary coil of the transformer in the
signal generation unit 120, thereby generating a control signal
used to switch the status of the SCR to on. Although the resistance
of the switched-on SCR is about several m.OMEGA. which is a lot
lower than the resistance of the MOV, the delay time required to
switch the status of the SCR from off to on is about 1 us, so that
only the end portion of the falling short pulse passes through the
SCR and flows into the ground. As a result, since the peak value of
the MOV let-through current 501 is about 2.5 kA, it can be seen
that most of the short pulse is blocked by the non-linear element
unit 110.
FIG. 6 is a view illustrating a simulation circuit which simulates
the operation of a surge protection apparatus according to a second
embodiment of the present invention, and FIG. 7 is a view
illustrating the results of a simulation performed by the
simulation circuit of FIG. 6.
Referring to FIG. 6, a simulation circuit according to the second
embodiment of the present invention includes a surge generation
source 60 for generating intermediate pulses which satisfy the
conditions of the PCI test of FIG. 1, the surge protection
apparatus 100, the filter 20 for removing high-frequency
components, and the load resistor Load_Z 30. Here, the filter 20
includes an inductor (506 uH) and a capacitor C1 (30 uF).
The surge protection apparatus 100 according to the second
embodiment of the present invention includes a non-linear element
unit 110 having an MOV, a signal generation unit 120 having a
transformer, and a switching element unit 130 having an SCR, like
the surge protection apparatus 100 according to the first
embodiment of the present invention.
Referring to FIG. 7, FIG. 7 illustrates the results of simulation
performed on current which passes through the non-linear element
unit 110 when an intermediate pulse (rising time: 1.5 .mu.s, FWHM:
3 ms, and peak current: 250 A) which satisfies the conditions of
the PCI test of FIG. 1 is input to the surge protection apparatus
100, that is, MOV let-through current 701, simulation performed on
current which passes through the switching element unit 130, that
is, SCR let-through current 702, and simulation performed on
current which passes through the load resistor 30, that is, load
resistor let-through current 703, respectively.
In detail, in the initial rising period of an intermediate pulse
generated by the surge generation source 60, the SCR, that is, the
switching element unit 130 is already turned on. Here, since the
peak value of the SCR let-through current 702 is about 250 A, it
can be seen that most of the intermediate pulse is blocked by the
switching element unit 130.
FIG. 8 is a view illustrating a simulation circuit which simulates
the operation of a surge protection apparatus according to a third
embodiment of the present invention, and FIG. 9 is a view
illustrating the results of a simulation performed by the
simulation circuit of FIG. 8.
Referring to FIG. 8, a simulation circuit according to the third
embodiment of the present invention includes a surge generation
source 80 for generating long pulses which satisfy the conditions
of the PCI test of FIG. 1, the surge protection apparatus 100, the
filter 20 for removing high-frequency components, and the load
resistor Load_Z 30. Here, the filter 20 includes an inductor (506
uH) and a capacitor C26 (30 uF).
The surge protection apparatus 100 according to the third
embodiment of the present invention includes a non-linear element
unit 110 having an MOV, a signal generation unit 120 having a
transformer, and a switching element unit 130 having an SCR, like
the surge protection apparatus 100 according to the first
embodiment of the present invention.
Referring to FIG. 9, FIG. 9 illustrates the results of simulation
performed on current which passes through the non-linear element
unit 110 when a long pulse (rising time: 0.2 s, FWHM: 23 s, and
peak current: 1 kA) which satisfies the conditions of the PCI test
of FIG. 1 is input to the surge protection apparatus 100, that is,
MOV let-through current 901, simulation performed on current which
passes through the switching element unit 130, that is, SCR
let-through current 902, and simulation performed on current which
passes through the load resistor 30, that is, load resistor
let-through current 903, respectively.
In detail, as soon as a long pulse raises, the SCR, that is, the
switching element unit 130 is switched on. Here, since the peak
value of the SCR let-through current 902 approaches 1 kA, it can be
seen that most of the long pulse is blocked by the switching
element unit 130.
FIGS. 10 and 11 are views illustrating simulation circuits which
simulate the operations of surge protection apparatuses according
to fourth and fifth embodiments of the present invention.
FIG. 10 illustrates an embodiment in which a zener diode has been
added to the surge protection apparatus 100 in order to prevent the
voltage of a control signal generated by the signal generation unit
120 from exceeding the allowable range of the switching element
130.
Further, FIG. 11 illustrates an embodiment in which a zener diode
and a capacitor have been added to the surge protection apparatus
100 in order to prevent the voltage and variation speed of a
control signal generated by the signal generation unit 120 from
exceeding the allowable range of the switching element 130.
FIGS. 12 and 13 are views illustrating simulation circuits which
simulate the operations of surge protection apparatuses according
to sixth and seventh embodiments of the present invention.
FIG. 12 illustrates an embodiment in which the signal generation
unit 120 includes resistors R1, R2, and R3 which are connected in
series and in parallel. The voltage of a control signal is
approximately determined as the following Equation 1. control
voltage=I.sub.nld.times.R1.times.R3/(R2+R3) (1)
Referring to Equation 1, R1<<R2+R3, and I.sub.nld indicates
current which passes through the non-linear element unit 110.
Further, FIG. 13 illustrates an embodiment in which a zener diode
is added to the signal generation unit 120 which includes the
resistors R1, R2, and R3 which are connected in series and in
parallel such that the maximum voltage of a control signal is
restricted to the breakdown voltage of the zener diode.
Next, a surge protection method will be described in detail with
reference to FIG. 14.
FIG. 14 is a flowchart illustrating a surge protection method
according to an embodiment of the present invention.
First, the surge protection method according to an embodiment of
the present invention is performed using a non-linear element unit
110, a signal generation unit 120, and a switching element unit
130.
Referring to FIG. 14, resistance rapidly decreases when the
difference in voltage between the two ends of the non-linear
element unit 110 is equal to or greater than a predetermined value
at step S100. In detail, the non-linear element unit 110 allows an
electrical surge, which is received from the surge generation
source 10, to pass through the non-linear element unit 110.
The non-linear element unit 110 according to the embodiment of the
present invention includes at least one of a varistor, a gas
discharge tube, and a transient voltage suppression diode.
The signal generation unit 120 generates a control signal in
response to current which passes through the non-linear element
unit 110 at step S200.
The signal generation unit 120 may include a transformer.
The signal generation unit 120 may include a transformer and a
zener diode.
The signal generation unit 120 may include a transformer, a zener
diode, and a capacitor.
The signal generation unit 120 may include one or more
resistors.
The signal generation unit 120 may include one or more resistors,
and a zener diode.
The switching element unit 130 switches the switching status
thereof in response to a control signal at step S300.
The switching element unit 130 according to an embodiment of the
present invention includes at least one of a thyristor and a relay.
Here, the thyristor is an SCR.
Therefore, the surge protection method according to the embodiment
of the present invention uses a non-liner element which has a rapid
response speed, a switching element which has the ability to
withstand a large amount of energy, and a signal generation unit
which connects the non-liner element and the switching element,
thereby blocking a high power surge and preventing a high energy
surge from flowing into facilities or apparatuses for a long period
of time.
According to an embodiment of the present invention, the surge
protection apparatus and the method using the same uses a non-liner
element which has a rapid response speed, a switching element which
has the ability to withstand a large amount of energy, and a signal
generation unit which connects the non-liner element and the
switching element, thereby blocking a high power surge and
preventing a high energy surge from flowing into facilities or
apparatuses for a long period of time.
Although preferred embodiments of the present invention have been
disclosed for illustrative purposes, those skilled in the art will
appreciate that various modifications, additions and substitutions
are possible, without departing from the scope and spirit of the
invention as disclosed in the accompanying claims.
* * * * *